Rotary expansion underreamer



Sept. 2, 1930.

J. J. SANTIAGO ROTARY EXPANSION UNDERREAMER 2 Sheets-Sheet l Filed Jan. l2, 1927 Inl/enfer .7a/7265:] Jawlbya IIHV Sept. 2, 1930. J. J. SANTIAGO v 1,774,763

I ROTARY EXPANSION UNDERREAMEH Filed Jan. 12, 1927 asneets-sneez 2 Inde/afar. ffy/726.5, lm/aya Patented Sept. 2, 1930 frarear v 'Ferries JAMES J. SANTIAGO, 0F LOS ANGELES, CALIFORNIA, ASSIG'NOR TO JOHN GRANT, 0F i LOS ANGELES, CALIFORNIA A ROTARY EXPANSION UNDERREAMER application ined January i2,V 1927. senai No. 150,580.Y

This invention has reference generally to underreamers and particularly to rotary eX- pansible underreamers such as are adapted to precede a well casing and drill a hole below the casing large enough that' the-casing may be lowered into it. Rot-ary eXpansible underl reamers are well known and .are in common,

useV so that no detailed description of their operationis here necessary.

The present invention has to do more particularly with improvements in that type of underreamer shown .in patent to Brown No.

1,454,843,"dated May 15th, 1928, and also in thepending applications of John T. Phipps,

said'patent and said applications such longi-` tudinal movement isl accomplished by having the .cutters longitudinally movable in or with reference to the tubular body.r the mandrel being stationary with'ielationto the tubular body. In the present invention, among other things, this relative arrangement is reversed,

` the interior mandrel and the body moving longitudinally with reference to'eacli other so thatthe Cutters are longitudinally istationary with reference to the body and move only in andout transversely. There are also several other improvements that are included within ther present invention; but all these improvements will be betternnderstood from the following detailed explanation of the l present preferred form of the invention,

which may be taken as typical and illustrative of the invention itself In the accompanying drawings:

' Fig. 1 is a longitudinal vertical central section with some parts in elevation showing.

my improved underreainer in its expanded condition Fig. 2 is a similar view showing the underreamer in its contracted condition;

Fig. 8 is a view partly in section-and'partly in elevation, the section being talrenr as indicated by line ,3 3 on Fig. 2; Y Fig. 4 is anlexterior elevation of the underieamer; ,Y Y "Fig, 5 is a crosssection on line V5%-5 o'f lFig. 2;

Figf 6 is a Fig2gand l Y Eig.v 7 is ak cross-sectionI on line 7-7 of. Fig. 2. A' n the drawings the body B of my improved underreamer is shown as made up of two parts, or abody proper and an extension;

an upper tubular body-or shell 10 and alower tubular body portion or extension 11, the

two being joined at the threaded joint 12 and shouldei'ing tightly against each other at t-he lshoulders 13. The upper tubular shell 10 has cross-section on line 6 6 of f throughits wall a number of slots 15 through Y which thefcutters v16 project. In the typical embodiment here illustrated I have shown thelslots and cutters as two in` number, but it will be well understood that there may be Y as many cut-ters as desired. I/Vhatever the V number of cutters, it is desirable that they be placed in symmetric relation about the vei'- Atical central axis of the reamer, so that the reaction forces .playing upon the cutters will kbe balanced yand will not tend-to shove the underreainer off to one side or another during drilling operations.

Typically the cutters may preferably be of rather flat formation, more or less in the shape of a Hat bar; and they may be provided with outer edges, `or outer and lower Y edges', with any suitable cutting elements. It lis common in underreamers .of this type to provide the cutters with sharp edges that shearaway the formation; and cutters of that type may be used in this underreamer, but I have preferred here to illustrate how I may provideV rolling cutting elements 17 which yproject somewhat beyond the outer edges ofA cutters 16 and operatev upon the formation in manners that are well understood. To Vpro- Yvide for the cutters moving inwardly to the position shown in Fig. 2 the slots l5 have enlargements 18 forming recesses into which vthe Vinnermost parts of rollers 17 may move. Thisarrangement will be apparent from an inspection of Figs. 2 and 4.

. lVithin the body of the underreamer there is a mandrel 20 provided at its upper end with any usual tool `ioint 21 for connecting with the drilling string. Vithin the upper body member 1() this mandrel has an enlargement 20a, Vand an inwardly extending flange 22 at the upper end of body portion limits the downward movement of the body with relation tothe mandrel and prevents the mandrel from being pulled out of the body.

Enlarged portion 2Oa or' the mandrel is provided with two diametrically opposed elo is 23 which tali-e the inner edges ofcutters 1G in the manner illustrated in the drawings. The inner edgesv ofthe cutters and the bottom surfaces of these slots are so relatively shaped that relative vertical Vmotion between the cutters and mandrel causes expanding and thrust bearing'the whole length of a cutter willgiv-e; and thctwo spaced bearings have the advantagethat the cutters and'body need not be movedlongitudinally as iar as they would have to be moved if there were a single thrust bearing the entire length of the cutter.,

Accordingly l make slots each 'ith a recess 23 in its bottom or inner surface, as willbe clearly seen from an inspection of v1. Each cutter has near or at its upperl end an inwardly projecting thrust lug` 1Gn which into rec' 23a when the cutter is in its lower positionY on the mandrel as shown in Fig. 2. At the same time that lug 16 lits into recess 28 another similar thrust lug 16') near or atthe lower end of the cutter then tits against the lover reduced par; et the mandrel, as shownin Fig. 2.' VThe mandrel y may be said to have two recessed portions tions et slots28 as shown in Fie'. 1.

portion comprising into which Vthe two thrust .lugs 16a and 1Gb move bach. when the cutters are in their collapsed or inner positions, the upper recessed Y the recess 20a and the lower recessed portion being comprised. in eiiiect, in the reduction oi diameter the mandrel bel w its enlarged part 20a.

In the expanded position the two thrust lugs 16:L and 1G of each cutter bear upon the bottom surface 23C oi the unrecessed porhe upper ends of both thrust lugs are beveled oli as, shown land the upper end of is similarly beveled at 23d yand the lower end or' the enlarged part el the mandrel is also .-;imil:=.rly beveled at 230, so that when the parte more 'from the position of Fig. 2 to the position of Fig. 1 the cutters will be 'forced outwardly by the wedging actions of these beveled faces. lWhen the cutters are thus torce/.l out to their expanded positions the cutters are solidly supported against inward radial thrust by having solid and widely spaced bearings upon the interior mandrel. And the cutters are solidly supported against torsional strains by reason of their titting 'fairly tightly in slots 15, being only loose enough in those slots to provide for easy movement. rihe cutters also lit in slots 23 ot the mandrel, but they lit those slots comparatively loosely for reasons to be hereinafter explained. And the cutters are prevented from being pulled or torn out ot their slots by direct radial outward movement by reason ot cutter projections 16e at their upper and lower ends, these projections bearing outwardly against the wall. or" body shell 10 above and below the slots 15.

rllhe lower reduced end 20 ot the mandrel projects down in to the bore 11u of body extension 11 and is there surrounded by a coiled spring 30 whose upper end. presses against a shoulder at the upper end of bore 11 and whose lower end is seated on a ring 31 carr`" l by the mandrel. 'lhe function of this sp lng is to press the body up with relation to the mandrel, tending always to move he parts to the position. of Fig. 1. The mandrel and body are moved to 'the relative positions shown in Fig. 2 rwhenever it is desired to collapse the cutters. This is done by the operator atthe top of the well when it is desired to lower the underreamer into the hole, and isv accomplished automatically when the underreamer raise-d u p into a casing. Vhen mandrel 20 is moved upwardly into the casing the upper ends of the parts of the cutters that project outside the body portion 10 come into contact with the lower end of the casing or with its shoe and hold the body .stationary while the mandrel moves on up to the relative position shown in. Fig. 9.. rllhen the bevels 16T on the upper ends of thecutters, acting against the casing shoe, cause the cutters to move into the positions shown in Fig. 2; and then the whole underreamer may be pulled up through the casing.

Lower body extension 11 is provided at its lower end with a threaded joint 35 to take a drilling` bit 36 of any desired type, but here typically illustrated as a fish-tail bit. To get circulating water to the fish-tail bit it is provided with a water duct 37; and mandrel 20 is likewise provided with a water duct 38 extending through its entire length and connecting with the water duct or hollow interior ot the drill pipe that is attached at the upper end of the mandrel. Water put down through through the mandrel 21.

liquid circulation goes directly yto the lowerl bit 36 to pickup its cuttings and a portion' goes directlyvto the.reaming.cutters to pick T he upper .end of lower body extension 11 screws into and shoulders upagainst the lower end of therupper body shell 10. The upper end of portion 11 is interiorlyfbeveled as at 40 to seat the bevel 23e of the mandrel, And the upperend oi 11v is provided with one 4or Amore .notches 41,.two being shown diametrically opposite each other. The mandrel` has at the lowerend of. its enlarged portion 2()a a corresponding .number otlugs 42 adapted to't more-or less loosely into notches 41 when the parts. 'are in the position shown in Figl.,` `f v L The lower endsof lugs 42are beveled, as shown at 42 so that the lugs will be guided into notches 41 as the partsmove tothe posi# tion of Fig. r1. y

Lugs 42 and notches 41 constitute-a positive `rotary drive between mandrel 20 and lower body extension 11, which carries the drilling .bit at-its lower end; and this lug and notch intercngagement not only provide such a positive drive, but also totally Vprevents any 1 accidental unscrewing of lower body member' 11 when the parts arein the position-of Fig.

1. This is the expanded-positionand is one in which the positive! drive is needed and the one in which unscrewing is most likely to occur. -Vhen'theunderreamer is collapsed,

as shown in Fig. 2, there is no need ot this pos-l itive drive and lock between the parts,.and

notches 41. Y

The rotary drive of the whole toolis This vmandrel drives cutters 16'by the engagement of those cutters in the mandrel slots 23, and `drives theupper body shell through the medium L vof cutters 16. The looseness of lit of the cutters in slots 23'allows a certainlatitude in the exact positions of notches 41, the exact position oi t-hose notches being determined by the position at which part 11 shoulders up against the lower end of part 10. "The rotary drive is usually in a right-handed direction looking down on the tool, or in the direction indicated by the arrowy in Fig. 5, and the thread at 12 will usually be a right-#handed thread,

'l C3 so that the drive tends to tighten up the lugs 42 from notches 41.

thread. The thread, however, cannot tighten up'any further than theinterengagem'ent of 41 and 42 allows, and,.consequently, the ac? tual'drive, or the major portion of'it, will be taken by 411and 42 ratherthan. by the threads 12.4 And if at any time it should be necessaryto rotate theexpanded tool back wardly, the jointvat 12 cannot bebroken. .The slight loosen'ess of cutters 16 in slots 23 also prevents the cuttersv becoming bound m-Y the sl ots by tine silt. Fluid can always play through the slots around t-he cutters and thusk keep the cutters-free.

JAlthough the construction is such that the lparts are all completely interlocked when the underreamer is Vexpanded and operating, and the parts are thus locked against any possible disconnection, at Vthe `same time` the construction is such that the underreamer is easily assembled and disassembled. To take. the underreamer apart it is only necessary to move mandrel up far enough to disengage 31and spring 30 have beenrremoved, eXten sion 11 maybe unscrewed and removed.y TheY joint or joint member at the top of. mandrel having been removed, the mandrel may then be slipped downwardly and out of shell 10,

or the shell slipped up oli?. the mandrel; and the cuttersmay then be moved inwardly and removed through the bottomof the shell.

The assembly is in the reverse order.

I claim: l, y l l 1. An underreamer of the [character described, comprising atubular .body with a Then after ring slot .through its .wall, a cutter VextendingV `Y throug'hsaid slot and confined'against longitudinal movement therein but movable lat` erally in and out through the slot,and a inandrel in the body, with relation to which it isv longitudinally movable, 4and having" a longif. tudi-nal slot in its surface taking the inner edge of the cutter and constituting a rotary driving connection between the mandrel. and the cutter; the kbody having a vlower .exten sion screw-threadedlyjoined -to it, 'and the:

mandrel and said body extension having in- Y terengaging lug and notch structures adapted to interengage when theanandreliis 'in a cerf,1

'tain position `with referenceto the body; y

2. An underreamer of the character dei" mandrel and saidvbody extension having in,- terengaging lug and notch structures; adapt-v iso ed to interengage when the mandrel is in a certain positionwith reference to the body, said lug fitting the notch loosely and said cutters 'fitting the mandrel grooves loosely.

3. An underreanier of the character de'- scribed, comprising a tubular body with a longitudinal slot extending through its wall` a cutter in said slot and projecting both out` side and inside the body wall, said cutter tf ting said slot to be immovable longitudinally therein but movable `laterally in and out throughsaid slot, a mandrel in said body and with relation to whichit is longitudinally movable, the inner edge of said cutter engage r ing said mandrel, and said cutter and mandrel being so formed that relative longitudinal movement between the body and mandrel causes lateral movement of said cutter, a body @extension screw-threadedly oined to one end f of ythe body, and an interengaging lug and notch formation on ,the mandrelvand said body extensionand adapted to be engaged by longitudinal movement of the mandrel;

4. An underreamer of the character de-l scribed, comprising a mandrel, a tubular body anda body extension removably joined to the body'atone end,rthe body and extension surrounding and being longitudinally movable on'thc mandrel, a cutter in the body adapted to be moved outward to expanded poM` lsition by longitudinal movement between the body and'mandrel in one direction, said cutter engaging the mandrel to rotationally interlock thebodyL and mandrel, and rotational interlocking means between the mandrel and said body extension adaptedl to be put into interlocking engagement by the relative lony*gitudinal rmovement which expands the cutters. w

5.7An underreamer yof the character described, v`comprising a jslottedrutter expanding mandrel having means at its upper end ttor connection to a rotary driving string, a

slotted body surrounding the mandrel, and a cutter engagingin both slots to be rotatively driven bythe mandrel and in turn to rotatively drive the body, the body and cutter being longitudinally movable with reference "to the mandrel to protract and retract the cutter, a body' extension movably joined u theretoi, and rotative interlocking means on panding position.y

, the mandrel and extension adapted to be en-.

gaged when the body and mandrel arerelatively in cutter protracting position and disengaged when the body and mandrel are relatively in cutter retracting position.

6. An underreamer of the character de scribed, comprising a body, a cutter movable therein, a cutter expanding mandrel movable relatively longitudinally in the body, a body extension removably mounted on the body, and rotational interlocking means on the mandrel and extension adapted to be engaged byV movement of the mandrel tol cutter ex- 7. An underreamer of the character described, comprising a body, a cutter movable therein, a cutter expanding mandrel formed to move the cutter outwardly by downward movement of the mandrel, a. lower body eX- tension into` which the lower end of themandrel projects, a mandrel operating spring surrounding the mandrel in the body vextension and tending to move the mandrel down, and rotational interlocking members on the mandrel and extension adapted to. be engaged by downward spring actuated Inovement ot' the mandrel.

by the spring actuated movement of the mandrel. f

9. In an underreamer of the character den u scribed, aftubular' slotted body, a slotted mandrel within the body, a cutter in the body slot and having its inner longitudinal edge in the mandrel slot, the cutter and mandrel being relatively longitudinally movable, the mandrel slot having a recess in its bottom intermediate its ends and the mandrel presenting at one end of the slot a surface which is sunk inwardly from the slot bottom, and the cutter having a pair of spaced lugs on its inner llongitudinal edge adapted one to lie in said recess and the otherto lie over the sunk mandrel surface when the mandrel and cutter are in a certain relative longitudinal position.

In witness that I claim the foregoing I have hereunto subscribed my name this 30th day of December, 1926.

` JAMES J. SANTIAGO. 

